Breast cancer is the most prevalent cancer in women that frequently spreads and recurs, thus leading to high mortality. Despite advances in surgery and treatment, standard of care still relies primarily on chemo- and radiation therapies aimed at killing the tumor cells. Evolutionary models predict that selective pressure imposed by these approaches causes survival of resistant clones that eventually re-activate the disease. Based on the central involvement of metabolic tumor cell alterations in cancer, this application follows the hypothesis that therapeutic normalization of tumor cell metabolism can halt breast cancer progression and prevent relapse. If successful, this approach would not eradicate all residual disease, but rather achieve and maintain a disease symptom-free state. In principle, treatment aimed at normalizing tumor cell metabolism would not impose selective pressure, and thus not favor penetration of escaping clones to drive recurrence. If successful, therapeutic metabolic reprogramming could become a critical component of breast cancer care and have revolutionary impact on overall outcome by reducing the mortality in breast cancer. Having identified a cause-and-effect relationship between aberrant tumor cell mitochondrial complex I function, oncogenic growth, and metastatic progression in breast cancer, this information translated into a new strategy, where normalization of the NAD+/NADH redox balance through treatment with NAD precursors led to inhibition of tumor growth and metastatic disease in xenograft models and interference with breast cancer progression in an oncogene driven transgenic model of spontaneous breast cancer. Based on these findings, the proposed study seeks to 1. Evaluate the efficacy of NAD precursor treatment in xenograft and transgenic mouse models of breast cancer progression, including combination with standard of care; 2. Employ targeted metabolomics to define the tumor cell NAD+/NADH metabolome in defined stages of disease advancement and treatment using ESI QQQ and NIMS technology, combined with XCMS metabolomic bioinformatics; and 3. Generate untargeted comprehensive metabolic profiles of progressive stages in breast cancer. The outcome from our study may identify therapeutic normalization of tumor cell metabolism, e.g. through NAD precursor treatment, as an effective, non-toxic way to silence breast cancer and prevent recurrence. The metabolome of breast cancer progression will empower the field and enable development of preventive approaches based on the concept of metabolic normalization. Interactive and collaborative efforts using the information generated will help to reduce the mortality in breast cancer patients. PUBLIC HEALTH RELEVANCE: This project addresses NCIs provocative question PQ21: Given the appearance of resistance in response to cell killing therapies, can we extend survival by using approaches that keep tumors static? Despite improvements in breast cancer surgery and treatment, the mortality of breast cancer patients has largely remained unchanged. A major underlying problem is that the disease frequently recurs, often years after initial adjuvant therapy was apparently successful. At present, the standard of care relies primarily on chemo- and radiation therapies aimed at eradicating rapidly dividing tumor cells. However these treatments are very likely to select more aggressive tumor cells that eventually re-activate the disease and are treatment resistant. Dormant or slowly dividing tumor cells with stem-like characteristics could also remain unaffected and lead to recurrence. We hypothesize that breast cancer cells, regardless of the initial transforming event and disease driving mechanism, rely on altered metabolic circuitry that allows the tumor cells to meet their energy needs not only for accelerated growth, but also for survival under changing access to nutrients and oxygen within niches of the tumor microenvironment. Based on our result and the central involvement of metabolic tumor cell alterations in disease progression, we predict that therapeutic normalization of the tumor cell metabolism can halt breast cancer progression and prevent relapse. If successful, this approach would not eradicate all residual disease, but rather achieve and maintain a clinical disease symptom-free state. In principle, treatment aimed at normalizing tumor cell metabolism would not impose selective pressure and thus not favor penetration of escaping clones or cancer stem cells that could drive recurrence. Therefore, therapeutic metabolic reprogramming could become a critical component of breast cancer care and have revolutionary impact on overall outcome by reducing the mortality in breast cancer.